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Title: Crosslinking of hemin to a specific site on the 90-kDa ferritin repressor protein

Incubation of a 90-kDa ferritin repressor protein (FRP) with small amounts of radiolabeled hemin resulted in the formation of a strong interaction between the two that was stable to SDS/PAGE. Of seven other proteins tested individually, only apohemopexin and bovine serum albumin showed similar crosslinking ability, albeit to a much lower extent. ({sup 14}C)Hemin specifically crosslinked to FRP in the presence of a 50-fold excess of total wheat germ proteins. Inclusion of catalase did not prevent the reaction of hemin with FRP, suggesting that H{sub 2}O{sub 2} is not involved. The subsequent addition of a stoichiometric amount of apohemopexin did not reverse the reaction. Exhaustive digestion of the complex with Staphylococcus aureus V8 protease produced a major labeled peptide of 17 kDa. These results show the existence of a highly specific, uniquely reactive hemin binding site on FRP.
Authors:
;  [1] ; ; ;  [2] ;  [3]
  1. (Washington Univ., St. Louis, MO (United States))
  2. (Univ. of Illinois at Chicago (United States))
  3. (Univ. of Missouri, Kansas City (United States))
Publication Date:
OSTI Identifier:
5933429
Resource Type:
Journal Article
Resource Relation:
Journal Name: Proceedings of the National Academy of Sciences of the United States of America; (United States); Journal Volume: 88:14
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; PROTEINS; CROSS-LINKING; CARBON 14 COMPOUNDS; FERRITIN; HYDROGEN PEROXIDE; PEPTIDE HYDROLASES; RECEPTORS; STAPHYLOCOCCUS; STOICHIOMETRY; TRACER TECHNIQUES; BACTERIA; CARBON COMPOUNDS; CHEMICAL REACTIONS; COMPLEXES; ENZYMES; HYDROGEN COMPOUNDS; HYDROLASES; IRON COMPLEXES; ISOTOPE APPLICATIONS; LABELLED COMPOUNDS; MEMBRANE PROTEINS; METALLOPROTEINS; MICROORGANISMS; ORGANIC COMPOUNDS; OXYGEN COMPOUNDS; PEROXIDES; POLYMERIZATION; TRANSITION ELEMENT COMPLEXES 550201* -- Biochemistry-- Tracer Techniques